Present-day surround sound systems often feature a number of loudspeakers, which should be positioned strategically around a listener in a room so that the listener is given the impression that the sound emanating from the loudspeakers originates from all around, or that a particular sound such as a voice originates from a virtual source, e.g. from a point to the left of the listener. These sound effects rely on a correct positioning of the loudspeakers, since it is the interaction of the lobes of sound originating from each loudspeaker that ultimately delivers the desired listening experience.
To assist the user in configuring—or placing—the loudspeakers correctly, present-day sound systems sometimes offer colour-coded connectors and sockets, i.e. the colour of the connector originating from, for example, the amplifier, matches the colour of the socket on the back of the loudspeaker. In practice it remains difficult for many users to perform the setup correctly, so that the speakers might be incorrectly placed about the room with respect to the television set. For example, the user might mistakenly connect the left surround speaker where the right surround speaker should be connected, or might entirely forget to connect a loudspeaker. Such an error significantly diminishes the quality of the combined audio and video experience, since the perceived sounds can appear to come from the “wrong” direction in relation to that which is seen on screen. The result of such configuration errors is that some of the listening effects might fail to be reproduced correctly, resulting in dissatisfaction on the part of the user of the sound system. Even if the loudspeakers are correctly connected, their placement about the room might still not satisfy requirements for the reproduction of the surround sound effects and a “sweet spot”—the area within a group of loudspeakers in which the sound is heard at its best. For example, the loudspeakers might be placed too far apart or too close together. Ultimately, it can be seen that the correct connection and placement of loudspeakers for a surround sound system is quite often beyond the capabilities of many of the owners of such systems.
In an attempt to address this problem, some systems comprise a configuration feature to configure the loudspeakers, once they have been connected, in an effort to give the listener a satisfactory listening experience. Such configuration systems attempt to determine the distances between the loudspeakers, since, when these distances are known, the sound system can optimise the signals to the line inputs of the loudspeakers. For example, US 2003/0031333 discloses a system for optimisation of audio reproduction, by having the user hold a portable sensor which detects the sound signals emanating from the loudspeakers, and transmits a signal to a processor which then optimizes the loudspeaker sound for the position at which the user is seated. However, this system requires active assistance on the part of the user. Furthermore, the user is compelled to have the portable (battery-operated) sensor at hand every time the position of a loudspeaker is changed, or whenever the user chooses to sit in a different position in the room. Should the sensor be misplaced at some point in time, the user can no longer initiate an optimisation of the loudspeaker sound. This proposed system offers no solution in the event of incorrect or missing loudspeaker connections.
In other proposed solutions, the distances between the loudspeakers are measured by causing test signals to emanate from the loudspeakers, and picking up the test signals by an array of microphones associated with the loudspeakers. The Convention Paper 6211 of the Audio Engineering Society (117th Convention) suggests an approach in which each loudspeaker is equipped with two dedicated microphones. A test signal is emitted by each loudspeaker in turn and is detected by the microphones of the remaining loudspeakers. However, a major disadvantage of this approach is that the test signal of the proposed system is issued in a separate setup procedure and can be heard by the user. Since it is necessary to perform the configuration as a separate process, the user must initiate the configuration, perhaps by means of a command given by the remote control of the tuner. However, since the user would probably have to consult the manual to determine the input command, he might not be inclined to carry out the configuration at all.
For many consumers, such configuration systems are simply too complicated and are perceived to be annoying, with the result that the user does not avail of them, or does not carry out the steps correctly, ultimately resulting in his dissatisfaction with the sound system.